I used a 270 adv duration with 9.1 to comp. ratio it worked really well on a ported 302 . I would hesitate to use it on anything less than 8.8 . what is recommended ? the 268 is a high energy Crane ? their recommended specs should tell you a recommended CR , and if new springs are needed . best to look at what the cam manufactures suggests .
Last edited by mikesnyhere; 04-14-2013 at 02:01 AM.